Control apparatus



June 9,1942. R. c. JONES 5 CONTROL APPARATUS Filed March 16, 1940INVENTOR Rm?! 0 Jones;

Patented June 9, 1942 CONTROL APPARATUS Ruel C. Jones, Forest Hills,Pa., assignor to Westinghouse Electric & Manufacturing Company, EastPittsburgh, Pa., a corporation of Pennsylvania Application March 16,1940, Serial No. 324,418

5 Claims.

My invention relates, generally, to control apparatus and, moreparticularly, to switches of the type which are commonly referred to asreversing switches an example of which is described in Patent No.1,872,342, issued August 16, 1932, to L. G. Riley.

It is the usual practice to provide such switches with secondary orauxiliary contact members in addition to the main contact members. Theauxiliary contact members are utilized for interlockswitch, which isdesigned to interrupt the power circuit, that the line switch willalways be opened before the main contact members of the reversing switchare opened and the line switch will not be closed until after the maincontact members are well closed. Therefore, it is essential that theauxiliary contact members be positive in operation and be operated atthe correct time with reference to the position of the main contactmembers on the switch.

Accordingly, an object of my invention, generally stated, is to provideauxiliary Contact members which may be readily applied to a switchhaving main contact members.

A more specific object of my invention is to provide auxiliary contactmembers for a switch of the type described in Patent No. 1,872,342.

Another object of my invention is to provide auxiliary contact memberswhich are actuated directly by the operating mechanism of a switch.

A further object of my invention is to provide auxiliary contact membersfor a switch which are actuated at definite times during the operatingcycle of the switch.

Other objects of my invention will be explained fully hereinafter orwill be apparent to those skilled in the art.

In accordance with my invention, the auxiliary contact members on aswitch are actuated by the same eccentric which actuates the operatingmechanism for the main contact members. The auxiliary contact membersare so disposed that they are not closed by the eccentric until it nearsthe end of its travel, thereby insuring that the main contact membersare closed prior to the closing of the auxiliary contact members.Likewise, the auxiliary contact members are opened prior to the openingof the main contacts.

For a fuller understanding of the nature and objects of my invention,reference may be had to the following detailed description taken inconjunction with the accompanying drawing, in which:

Figure l is a view, in front elevation, of a switch constructed inaccordance with my invention;

Fig. 2 is a view, in plan, of the switch shown in Fig. l; and

Fig. 3 is a detail view of a portion of the switch shown in Fig. 1.

Referring to the drawing, a switch II), which is illustrated therein, isof the same type as the one described in the aforementioned Patent No.1,872,342. The switch l0 may be utilized for reversing the direction ofthe flow of current through motors or other electrical apparatus bytransferring the motor conductors from one electrical circuit toanother.

Since the switch I0 is fully described in the aforementioned patent, itwill not be described in detail in the present application. Briefly, theswitch it comprises three stationary contact members l2, l3 and M whichare mounted upon a panel The fixed contact members are disposed to beengaged by two movable contact members I5 and I6.

With a view to providing a simple and positive means for actuating themovable contact members l5 and I6 into and out of engagement with thestationary contact members, an air engine 2| is also mounted on thepanel I. The air engine 2| is of well known construction and comprisespistons 23 and 24 which are disposed in cylinders 25 and 26,respectively. Admission and exhaustion of air to and from the cylinders23 and 24 may be controlled by magnet valves (not shown) also of a Wellknown type. The pistons 23 and 24 actuate a rack 21 which rotates apinion 28.

In order that the contact members l5 and I6 may be actuated by the airengine 2|, work arms 3| and 32 are connected to the contact members Hiand I6, respectively. Each of the work arms comprises a pair of spacedbars which are pivotally mounted at their upper ends upon the frame ofthe air engine 2| and are pivotally connected at their lower ends to themovable contact members, The work arms 3| and 32 are actuatedsimultaneously by a cross-head 33 which, in turn, is actuated by thepistons of the air engine 2|. In the present embodiment, the cross-head33 is actuated by means of pivotally mounted lever arms 34 which areactuated by eccentric pins 35 on the pinion 28. A bearing block 36 ismounted on each eccentric pin 35 and is disposed between the forked armsof each one of the lever arms 34, thereby actuating the lever arms asthe eccentric pin 35 is rotated back and forth by the rack 21.

In order to apply pressure to the contact members l5 and I6 to maintainsufficient pressure between the contact members of the switch to enablethem to conduct currents of a high value, springs 31 and 33 areinterposed between the cross-head 33 and the work arms-3| and 32,respectively. The springs 31 and 38 are so disposed that the cross-head33 applies pressure to the movable contact members I5 and I6 when theyare actuated to their opposite positions from that shown as well as inthe positions shown. Maximum pressure is applied to the contact memberswhen the eccentric pins 35 are in either one of their extreme positionsof travel.

It will be seen that the contact members are retained in a closedposition by the eccentric pins 35 and the levers 34 when the eccentricpins are moved past center. Therefore, it is not necessary to maintainair pressure in the cylinders in order to maintain the switch in eitherof its closed positions.

As explained hereinbefore, it is customary to provide switches of thetype herein described with secondary or auxiliary contact members whichare used for interlocking purposes in the control system of which theswitch forms a part. In prior constructions, the interlock was of thetype in which sliding auxiliary contact members were operated bymovement of the lever 34 through a link connected to the lever 34.Considerable difliculty has been experienced in properly adjustinginterlocks of the sliding type because of the fact that there is verylittle movement of the lever 34, while the springs are being deflectedafter the main contact members touch. Since the purpose of the interlockis to prevent the line switch, which is connected in the power circuitwith the main contact members of the reversing switch, from closinguntil the reverser is operated and essentially the maximum pressure isapplied to the contact members, it is desirable that the interlock notbe closed until the eccentric pin has reached approximately its maximumposition of travel, at which position maximum pressure is applied, asexplained hereinbefore.

In accordance with my invention, the movei ment of the bearing block 36in the forked operating lever 34 is utilized to actuate the auxiliary orinterlocking contact members. As shown by the curve 39 in Fig. 3 inwhich the bearing block movement is plotted against rotation of theoperating pinion 28, there is very little movement when the eccentricpin is at the center of the piston travel. However, as the eccentric pinmoves toward the end of its travel, the vertical movement increases inrate until it attains a maximum as the eccentric pin reaches the extremelateral position and is just about to go over center. Since there isstill a slightly additional movement to securely lock the lever andcontact mechanism in place, this movement is utilized to operate asimple interlock.

As shown in the drawing, each interlock comprises a piece of temperedclock spring steel 4| one end of which is connected to a terminal 42 andsecured to a terminal block 43 by means of a screw 44, and the other endof which is bent back on itself to form a bend of a large radius. Theterminal block 43 is secured to the panel H by a screw 45. The spring 4|carries a movable contact member 46 which is disposed to engage astationary contact member 41 connected to a terminal 48 and mounted onthe channel H by a screw 49. The stationary contact member 41 may beadjusted in position by means of a screw 5|.

A fiber plug 52 is disposed in the end of the bearing block 36 to engagethe bent end of the spring 4| to deflect the spring and close thecontact members 46 and 41, thereby completing a circuit through thesecontact members. In this manner, mechanical jarring of the auxiliarycontact members is prevented by the resiliency of the spring 4| andalso, allowance is made for slight variations in travel of the fiberblock 52.

Referring again to Fig. 3, which illustrates the position of theeccentric pin 35 and the fiber block 52 when the main contacts of thereversing switch first touch as the eccentric pin is being operatedtoward the position shown in Fig. 1, it will be seen that the tip of theplug 52 is at the point 53 on the curve 39. Furthermore, it will be seenthat the spring 4| is not engaged by the plug 52 until it has almostreached its extreme position at the point 54 on the curve 39 asillustrated by the dot and dash lines. Thus, the contact members 46 and4! are not closed until the eccentric pin is substantially at the end ofits travel and maximum pressure has been applied to the main contactmembers of the switch, as explained hereinbefore.

As shown in the drawing, an additional pair of auxiliary contactmembers, similar to those described, is provided on the right hand sideof the switch ID. This pair of contact members is operated in the samemanner when the eccentric pin 35 is at its other extreme position oftravel and the main contact members 5 and I6 are thrown to theiropposite positions.

From the foregoing description, it will be seen that I have providedauxiliary or interlockin contact members for a switch which are positivein operation and are not closed until after the main contact members ofthe switch are closed and substantially full pressure is applied to themain contact members. Likewise the auxiliary contact members aredefinitely opened before pressure on the main contact members is reducedand the main contact members are opened. Therefore, the interlock hereindescribed may be safely utilized to control the operation of aprotective switch which is connected in a power circuit with a reversingswitch of the type herein described. It is obvious that the interlockdisclosed in the present application may be utilized with switches ofother types and for other purposes than that herein described.

I do not desire to be restricted to the particular form or arrangementof parts herein shown and described since it is evident that they may bechanged and modified without departing from the spirit and scope of myinvention as defined in the appended claims.

I claim as my invention:

1. In a switch, in combination, a pair of main contact members,resilient means for pressing said contact members into engagement, arotatable eccentric pin for compressing said resilient means, a pair ofauxiliary contact members, and means rotating with said eccentric pinfor actuating said auxiliary contact members into engagement by rotativemovement of said eccentric pin only after said resilient means iscompressed.

2. In a switch, in combination, a pair of main contact members,resilient means for pressing said contact members into engagement, meansfor compressing said resilient means, a rotatable eccentric pin foractuating said compressing means, a pair of auxiliary contact members,and means rotating with said eccentric pin for actuating said auxiliarycontact; members into engagement by rotative movement of said eccentricpin only after said resilient means is compressed.

3. In a switch, in combination, a pair of main contact members,resilient means for pressing said contact members into engagement, acrosshead for compressing said resilient means, a rotatable eccentricpin for actuating said crosshead, a pair of auxiliary contact members,and means carried by said eccentric pin for actuating said auxiliarycontact members into engagement by rotative movement of said eccentricpin when said resilient means is substantially fully compressed.

4. In a switch, in combination, a pair of main contact members, aneccentric pin rotatable to a plurality of positions for actuating saidcontact members into and out of engagement, a pair of auxiliary contactmembers, and means rotating with said eccentric pin for actuating saidauxiliary contact members into engagement by rotative movement of saideccentric pin at each of its extreme positions of travel, each pair ofauxiliary contact members being closed only when said eccentric pin hasreached substantially the end of its travel in a predetermineddirection.

5. In a switch, in combination, a main stationary contact member, a mainmovable contact member disposed to engage the stationary contact member,a lever mechanism for actuating said movable contact member into and outof engagement with said stationary contact member, an eccentric pin foractuating the lever mechanism, an auxiliary stationary contact member, aresiliently mounted auxiliary movable contact member disposed to engagethe auxiliar stationary contact member, and means carried by saideccentric pin for biasing said auxiliary movable contact member intoengagement with the auxiliary stationary contact member after said levermechanism has been operated to actuate the main movable contact member.

RUEL C. JONES.

